The Art of Water Recovery

Imagine that you run a company that sells bottled water. You spend lots of money, and use lots of energy, pumping the water out of the ground, purifying it and transporting it for sale. Then, one day, you discover that a large number of bottles never make it to the stores. They are falling through holes in the trucks.

Wouldn’t you want to know what could be done about it? Wouldn’t you be crazy to allow the situation to continue?

Well, that’s what’s happening with many water utilities in the United States. The Environmental Protection Agency estimates (pdf) that public water systems lose, on average, one-sixth of their water — mainly from leaks in pipes. The E.P.A. asserts that 75 percent of that water is recoverable. (In truth, the volume of leakage in the nation’s 55,000 drinking-water systems is unknown, because few conduct water audits using the standards established by the International Water Association and the American Water Works Association.)

It’s been widely reported that California is experiencing its worst drought in history. But take a look at the United States Drought Monitor: much of the country is abnormally dry or in drought. Internationally, the problem is even more serious. The World Bank reports that, over the next decade and a half, water availability may fall 40 percent short of global need (pdf).

Meanwhile, utilities in the developing world are hemorrhaging water. The World Bank estimates that water systems have real losses (leakages) of 8.6 trillion gallons per year, about half in developing countries (pdf, 11MB, p.6). That’s enough to serve 150 million Americans (and we use a lot of water!)

Why don’t utilities do more to recover it?
The results can be substantial. Consider Manila. From 2009 to 2013, with project management from an innovative young company called Miya, the utility that provides water to the western zone of Manila, Maynilad, reduced its so-called non-revenue water from 1.5 billion to 750 million liters per day, mainly by stemming leakages (pdf).

During that period, according to Irineo L. Dimaano, who directs Maynilad’s non-revenue water work, the company reduced the volume of water it supplied into the system by 400 million liters per day, while simultaneously serving an additional 1.3 million people, increasing the proportion of customers who receive 24-hour service to 97 percent from 65 percent, improving water pressure, and doubling annual revenues.

This is an extreme case of the potential gains that can be made by tightening up a water system. But water leakage is widely overlooked — largely because it is technical and dull and politically unattractive. “Water loss is unsexy,” said Mary Ann Dickinson, president of the Alliance for Water Efficiency. “There’s no ribbon cutting for new plants. If you announce that you’ve recovered a million gallons a day, it looks like you weren’t managing your system right in the first place.”

Today’s budding water loss industry grew out of the efforts of a bunch of brilliant, obsessive, far-thinking engineers in Britain who started something called the National Leakage Initiative in the early 1990s. Led by a man named Allan Lambert, they developed a methodology for categorizing and quantifying water leakage, and predicting losses, so they could rigorously determine how to reduce them.* This was vital in Britain, which had some of the world’s oldest water systems.

Their efforts were famously successful. Lambert later led a task force for the International Water Association, which established new standards for water accounting (pdf). In recent years some states, notably, California, Georgia, Tennessee and Texas, have begun requiring that utilities conduct water audits, but they have not mandated targets for water loss reduction. In fact, no state mandates targets for water loss reduction using the new standards.

Today, the emergence of companies that specialize in reducing water losses, like Miya, represents an important step forward, much like the emergence of energy service companies in the 1970s and 1980s to reduce energy use.

Miya was founded in 2006 by Shari Arison, an American-Israeli businesswoman and billionaire. Over the past eight years, the company has assembled a team of water loss experts and deployed them in a dozen countries. What distinguishes its work is its whole system approach: it looks at a water system the way a doctor looks at the body’s circulatory system.

Water systems are counterintuitive. It’s commonly thought that water leakage can be solved simply by replacing the worst pipes, but that’s usually just a short-term fix. The real key is understanding and managing pressure.

“When you have a pressurized system, what you do in one place affects all other places,” said Meir Wietchner, Miya’s chairman. Replace a leaky pipe segment and the pressure will increase in other segments and more leaks will sprout. “It’s simple physics,” he added. “And the larger the pressure the larger the leakage. If a hole that’s receiving one unit of pressure will leak X gallons per day, with 2 units of pressure it will leak 4X, and with 3 units pressure it will leak 9X. It’s a square function.”

One of Allan Lambert’s insights was to separate leaks into “bursts” and “background” losses (pdf). “It isn’t the main leaks that cause the most loss of water,” he said. “It’s the long-running leaks that go on for months or years that aren’t detected. One leaking toilet will lose as much water in two years as a burst in a four-inch main for a full day.”

So how do you fix and manage a system that’s leaking in tens or hundreds of thousands of places — and how do you do it cost effectively?

Related

That was the problem that Glen Laville, the general manager for the Bahamas Water and Sewerage Corporation (W.S.C.), was facing. Before 2012, to serve the water needs of New Providence, the largest island in the Bahamas, each day the W.S.C. was supplying some 12 million imperial gallons to the system — and each day it was losing 6.5 to 7 million gallons. Over the years, piecemeal solutions had been tried — mainly replacing big pipes — but the leakage always returned.

Photo

A cracked PVC pipe in an area of extremely high leakage in New Providence.Credit Miya

In 2012, Miya won an $83 million 10-year contract to advance a more sustainable solution. “The other companies wanted to come in and change 20 to 30 miles of pipeline,” said Laville. “We weren’t looking for someone to come in and just give us a new infrastructure. We wanted a holistic approach.”

One selling point was that 30 percent of the company’s fees would be based on performance. To earn those payments, Miya would have to bring the leakage down to 2.5 million gallons per day by year five, and to 2 million gallons per day by year seven — and the levels would have to be maintained for the duration of the contract. (Reductions below that level become cost prohibitive.)

Work started in 2012. The company spent most of the year studying the problem, examining every component of the system, explained Sofia Kanellopoulou, the project manager for the Bahamas, who was formerly a deputy director of the Athens water utility. The system had 44,000 service connections — pipes from water mains to customers — and, in line with Lambert’s findings from Britain, that’s where 90 percent of the leaks were occurring.

There were many reasons for the leaks: Service connections hadn’t been installed with proper pipes and fittings; water from the desalination plant contained substances that were damaging pipes; the water table was high, with saline intrusion from the sea, which was also corrosive.

Then there was a secondary problem exacerbated by the leakage itself. With so much water lost, the system sometimes ran short of supply, and water had to be rationed. (Not for tourists, though. The big hotels typically supply their own water.) Water rationing is common in the developing world — but the consequences are poorly understood. When pressure drops to zero in pipes, contaminants in the surrounding ground — including salt water or waste from nearby sewage lines — can get sucked into the water lines, which is terrible for public health. And when you empty a system and then re-pressurize it, the resultant “surge wave” further damages pipes. A steady, moderately low level of pressure is best — just as in the human body.

Finding leaks is painstaking work. It starts by dividing a large system into smaller “district metered areas” where pressure can be independently monitored and controlled. You analyze tons of data with computer programs. You stay up late. Most of the water moving through a system in the middle of the night is leakage. Because it’s too costly to replace every leaky pipe or connection, the key is to figure out how to save the greatest volume of water with the least possible effort.

To do this, leak detectors with sophisticated sound equipment fan out around cities in the wee hours, listening closely to gauge the size of leaks below ground. (In the Bahamas that didn’t work, however, because of electrical interference from power lines.) Fortunately, the water pipes are only a few feet under the ground, so access was relatively easy.

To date, the system has been partitioned into 30 pressure zones, and will be further subdivided. More than 2,500 leaks have been repaired, using materials that are suitable for local conditions. Meters have been installed and the system pressure is being carefully managed. Water losses are already down to 4.5 million gallons per day, reports Laville. This past May, the W.S.C. needed to supply only 10 million gallons per day to meet customers’ needs, two million less than in 2012.

“Last year, with two desalination facilities running at full capacity, we had to ration water,” said Laville. “Within nine months of starting this project, we got to a point where we no longer had to ration the water. And we’re now at a point where we can tell the desalination plant to cut back on their supply.”

Over the 10 years, Laville estimates that the project will save 10 billion gallons of water, 7 million gallons of diesel, and 33 gigawatts of electricity. “In the 10 years, the project will pay for itself,” he added. “It’s almost a no-brainer.”

It’s a major improvement. But Paul Fanner, Miya’s project director in the Bahamas, comments: “We’re not doing anything that special. We just have to get all the things right. If you do one or two things, it doesn’t work. It’s all interrelated. It’s not rocket science, but to do it well is very rare.”

What Laville likes most is that Miya has just four people from outside the Bahamas working on the project. “That is an amazing thing for a project of this size and complexity,” he said. “They come in, they train locals, they transfer that technology, and then they let them loose. At the end of 10 years, we’ll have a trained work force to continue the work.”

Efforts to reduce water leakage are spreading around the world, albeit slowly (pdf). There have been big water recovery gains in Cambodia, Brazil, South Africa and Malaysia, among other places. But despite the fact that it’s good for business, good for customers, and good for the environment, bankers and politicians still favor expanding production when there are shortfalls (even if the expanded production will have to flow through the old leaky pipes!)

“In many areas of the world, there’s no need to produce more water if we just cut waste,” said Wietchner. “But a lot of people are not willing to admit the level of loss they have.”

Back to California. There are currently 17 desalination plants in the planning or construction stages in the state. The $1 billion Carlsbad Desalination Project — the largest desalination facility in the Western Hemisphere — will produce 50 million gallons of potable water daily for San Diego county.

But how much water could be saved by reducing leakages in California?

One study (pdf) conducted for the California Public Utilities Commission examined audits done by 17 water utilities and found that losses were 1.6 to 6.6 times higher than optimum levels. (See footnote, for a brief explanation of these numbers, known as Infrastructure Leakage Indices.) Assuming that 40 percent of the losses could be recovered economically, the study’s lead author, Reinhard Sturm, estimated potential savings at 113 billion gallons per year — equivalent to the annual production of six Carlsbad projects.

It’s vital to consider the impact on energy use and the environment. Water is often lost between the main pipe and the customer, which means it has already been extracted, treated and transported a very long way. That’s expensive. All that energy is lost — and more has to be used — and that, of course, increases carbon emissions. California’s water system is already the state’s largest single energy user. At the same time, desalination plants are energy intensive. Electricity accounts for roughly half the cost of their water.

As noted, some states are requiring utilities to report water audits. And around the country, individuals like George Kunkel of the Philadelphia Water Department and Chris Leauber of the Water & Wastewater Authority of Wilson County, Tenn., and companies like Water Systems Optimization and Cavanaugh, are leading the way.

But given the scope of the problem – and the fact that utilities are asking their own customers to conserve water – far more attention is warranted. With properly conducted water audits and loss reduction targets, officials would be in a position to determine if shortfalls could be better met by reducing leakage than by increasing production. Right now, many have no way to know.

Part of the problem is good old-fashioned complaisance. “U.S. folks have the impression that they are already system tight and they don’t need to do much more,” said Mary Ann Dickinson, of the Alliance for Water Efficiency. “I believe they are mistaken and they need to run their numbers to verify where they are.”

What’s missing most is serious focus from governments, particularly at the state level. “Government policy makers are not paying attention to leakage,” added Dickinson. “We want to see every state requiring their water utilities to look at this. That’s what they did in the U.K., and the huge turnaround that occurred there is what we need to see in the U.S.”

* Note for wonks: Most people refer to water leakage in terms of percentage losses. However, Allan Lambert, the godfather of water-leakage reduction, argues against using percentages because they fail to provide a meaningful or consistent measure of the quality of a water system (and are easily manipulated). For instance, if you add a few large customers to a leaky water system and make no repairs, percentage leakage will drop. (It will appear that you have improved things when you have only increased the denominator.)

Lambert favors a measure called Infrastructure Leakage Index (I.L.I.), which compares real losses to the lowest level that is technically achievable for a particular system. An I.L.I. of 4 means you’re losing four times as much water as you would be losing if your system was optimally managed. I.L.I.s can be used to compare different systems, and also to estimate how difficult, and therefore costly, marginal gains will be to achieve.